A conventional video playback device includes: multiple memories configured to store content data; multiple decoders installed for the respective channels, and configured to decode the content data which are read from the memories and output the decoded data; an L2 switch configured to connect the multiple memories and the multiple decoders together through an IP (Internet Protocol) network. This type of video playback device is likely to fail to play back content data normally, in a case where some abnormality occurs in the IP network or the L2 switch. A conventional practice for coping with such a case is that: one video playback device is actually used while a backup video playback device is ready; and once an abnormality occurs in the video playback device in actual use, the backup video playback device takes over the playback operation (see JP, P2001-144705A, for example). In other words, once a trouble occurs in the IP network or the L2 switch in actual use, the video playback device in actual use is replaced with the backup video playback device, and thereby the content data is normally played back.
However, the above-described method needs both the video playback device in actual use and the backup video playback device. For this reason, this method entails problems that: costs for the system construction are high; and the system is large in size.